1. Field of the Invention
The present invention generally relates to cleaning a floor of a room enclosed by a wall perimeter, and more specifically to a self-propelled or self-running cleaning machine with automatic control.
2. Description of the Related Art
A prior art self-propelled cleaning machine is disclosed in Japanese Laid Open Patent Application No. Sho 60-93522. The overall structure of the machine is illustrated in FIGS. 1a to 1c, and a control circuit for controlling the operation of the machine is illustrated in FIG. 2.
Referring to FIGS. 1a to 1c, the prior art cleaning machine comprises a main body 1. A bumper 2 is provided around the main body 1, and a plurality of distance sensors 3 are mounted on the front side of the bumper 2 for detecting an obstacle in front of the body 1 and sensing a distance from the body 1 to the object by transmitting and receiving ultrasonic waves.
A front wheel 4, left and right rear wheels 5a and 5b, a dust suction nozzle 6, a dust collection chamber 7 for collecting dust sucked up by the nozzle 6, and a sweeper motor 8 are mounted on the bottom of the main body 1.
Wheel motors 10a and 10b are also mounted on the bottom of the main body 1, and are connected through speed reduction devices 9a and 9b, which comprise reduction gears (not shown), to the rear wheels 5a and 5b. Sensors 11a and 11b are operatively connected to the rear wheels 5a and 5b for sensing rotation of the wheels 5a and 5b and thereby the distance that the machine has run.
A control device 12 is also mounted on the main body 1 for controlling the self-propelled cleaning operation of the machine. The main body 1 further supports a power supply device 13 for applying electric power to the sweeper motor 8, the wheel motors 10a and 10b and the control device 12.
As illustrated in FIG. 2, the control device 12 comprises a running control circuit 14 for controlling the self-propelled running operation or movement of the cleaning machine. A position discrimination circuit 15 senses the position of the cleaning machine in two dimensional coordinates (X - Y coordinates), according to units of distance that the machine has run. An operation section 16 is provided for turning the cleaning machine on and off, switching running modes, setting a cleaning start position, and controlling the sensitivities of the sensors.
A remote control transmitter 17 and receiver 18 are provided for remotely controlling the cleaning machine. A motor driving section 19 controls driving power for the motors. A contact sensor 20 senses when the bumper 2 contacts an obstacle. An amplifier 21 amplifies signals from the sensors and applies the amplified signals to the running control circuit 14.
The running distance sensors 11a and 11b are part of the position discrimination circuit 15, and sense the distance that the cleaning machine has run, for example, by generating a pulse for each increment of rotation of the wheels 5a and 5b. A direction sensor 23 senses or detects changes in the running direction of the cleaning machine. The running control circuit 14 further comprises a central processing unit (CPU) 24 for controlling the overall operation of the machine, input/output circuits 25 for inputting and outputting sensor and control data between the CPU 24 and the position discrimination unit 15, a read only memory (ROM) 26, and a random access memory (RAM) 27.
A program for controlling the operation of the machine, as well as operational data, are stored in the RAM 27. A clock generator 28 feeds clock pulses to the CPU 24 for operation of the running control circuit 14. An interrupt controller 29 handles interrupts that are generated by the machine for suitable processing by the CPU 24.
The operation of the machine illustrated in FIG. 2 will be described with reference to FIGS. 1 to 3.
The user initially places the cleaning machine at a start position S in an area to be cleaned as shown in FIG. 3a, and then controls it to run straight to a first turning point P1 using the remote controller transmitter 17.
The motor driving section 19 of the cleaning machine drives the wheel motors 10a and 10b under control of the running control circuit 14. When the cleaning machine reaches a point P1, the user presses a Turn-Left key on the transmitter 17, the direction sensor 23 senses the change in running direction of the machine, and the running distance sensors 11a and 11b sense and store the distance between the points S and P1. The cleaning machine then runs straight to a second turning point P2.
In an essentially similar manner, the user controls the cleaning machine using the remote control transmitter 17 to run around the periphery of an area to be cleaned that is defined by turn points P2-P3-P4-P5-P6-P7 and an end position E. The running control circuit 14 senses and memorizes or stores the distances between these positions and the turning directions as X-Y coordinates based on the output signals from the direction sensor 23 and the running distance sensors 11a and 11b.
Then, based on the memorized or stored data, the running control circuit 14 divides the overall cleaning area into a plurality of cleaning blocks B1 through B7 by drawing longitudinal and transverse lines which pass through the turning points P1 through P7, as well as the start point S and end point E as illustrated in FIG. 3b. The cleaning blocks B1 through B7 are then combined into areas A1, A2 and A3 as illustrated in FIG. 3c based on the correlation between the adjacent cleaning blocks.
The user then presses a key on the remote controller transmitter 17 to order the control device 12 to drive the sweeper motor 8 and the wheel motors 10a and 10b so that the main body 1 of the cleaning machine is run in a reciprocating path with alternating turns in opposite directions as illustrated in FIG. 3d so as to clean the combined cleaning areas A1, A2 and A3, one by one.
The cleaning machine senses proximity to front and side obstacles and distances from the obstacles using the distance sensor 23, and senses contact with obstacles using the contact sensor 20. This enables the cleaning machine to change direction as illustrated in FIG. 3d and make any necessary corrections to the running path as required. As the cleaning machine self-runs along the path of FIG. 3d, it performs cleaning by sucking dirt into the dust collection chamber 7 through the dust suction nozzle 6 under power of the sweeper motor 8.
However, the prior art self-running cleaning machine is complicated and inconvenient to use in that the user is required to manually control the machine to run along the periphery of the area to be cleaned using the remote controller transmitter 17. If the user does not accurately control the machine during this operation to define the contour or periphery of the cleaning area, the cleaning area will not be defined accurately, and the room will not be cleaned effectively.